GETTING AROUND TOWN SAFELY ON FOOT Compared with other major cities around the world, like Paris with its circuitous arrondissements and Tokyo with its bewildering maze of themed districts, New York City, especially the borough of Manhattan, is a relatively easy place to navigate.   For the most part, the avenues run north and south and the streets go east and west in numerical order. There are exceptions, like Greenwich Village and SoHo, which are arranged